1. Field of the Invention
This invention relates to a dispensing syringe, and particularly to a dispensing syringe for dispensing a fluid glue made of cyanoacrylate.
2. Description of the Prior Art
In the conventional glue, such as Alkyl-2-cyanoacrylate which is usually referred as instant glue or three-second glue, the cyanoacrylate can quickly be polymerized at room temperature without adding catalyst. Suck quick polymerization is caused by a weak-base substance to make an anionic polymerization. Since such glue has a strong gluing force, it is subject to causing a preservation and storage problem in a container after each use.
Conventionally, the glue of cyanoacrylate is loaded in a container made of a high density polyethylene; in order to facilitate dripping, such container is furnished with an elongate dripping tube on the sealing cap or the like; the dripping tube is to be closed with a cap. According to the aforesaid package, the outer end of the dripping tube is sealed completely. Before the first time use, the sealed outer end of the dripping tube has to be stabbed through with a needle point, i.e., to make a fine hole; then, the fine hole is subject to being blockaded or sealed With the glue therein; in that case, the fine hole will be unable to stab through with a needle; the only way to open such dripping tube is to cut off a small part thereof so as to let the glue drip out again. After one part of the front end of the dripping tube is cut off, the hole of the dripping tube will be larger than the last one to result in having more air to enter the container; as a result, the glue in the container will soon become polymerized and solidified, i,e., becoming useless.
In a conventional point-gluing machine, the dispensing syringe is mounted to the front end of a dispensing tube of such machine; the dispensing syringe comprises a syringe stem and a syringe seat; both ends of the syringe stem are flat openings; one end thereof is inserted into the center of: the syringe seat, while the other end thereof extends at a suitable length for dispensing a glue. The syringe seat is fastened, with a screw-method, to the front end of a dispensing tube of the point-gluing machine. The dispensing quantity of the glue is controlled with the point-gluing machine. If the dispensing syringe of, the point-gluing machine is tried to mounted on a glue container, it will be impossible because of the dripping tube on the front end opening of the container is not provided with a conic cylinder opening, i.e., the dispensing syringe is unable to be mounted to a container for containing cyanoacrylate glue.
Since the dripping tube of the conventional glue container is a sealed type of dripping tube, i.e., having no a through hole to let the dispensing syringe to insert therein, one end of syringe stem of the dispensing syringe is provided with a bevel opening, which extends into the center of the conic cylinder opening. Since the dispensing syringe is inserted into the elongate dripping tube with stabbing method, which has been disclosed in a Taiwan patent application Ser. No. 81215092, in which a dispensing syringe has a bevel opening to be stabbed into the front end center of an elongate dripping tube on the container so as to let a glue therein flow out. In practise, the bevel opening is stabbed into the front end of the container, but the outer atmosphere is subject to entering the container if the front end of the dripping tube is not quite fitted with the conic cylinder opening, i.e., the outer surface of the dripping tube is unable to have an airtight contact with the conic cylinder opening of the syringe seat; in that case, the front end of the dripping tube and the bevel opening will be sealed by the glue after being solidified. Since the inner surface of the syringe stem is a smooth surface, the syringe stem is subject to being blockaded with the glued solidified, and then the dispensing syringe will become useless.
In the foresaid prior art, a Japan manufacturer has made a container with a conic cylinder in the front end thereof to fit with the dispensing syringe; of which one end has a bevel opening to stab into the front end of the glue container. The conic cylinder of the container is used for obtaining an airtight contact with the conic cylinder opening of the syringe seat. The inner surface of the syringe stem is a straight and smooth surface to facilitate the glue to flow out. According to the instruction of the aforesaid product, after the glue is used each time, a user should put some mouth water or natural water on the front end of the syringe stem so as to enable the glue to be polymerized as a solidified layer to prevent the atmosphere from contacting the glue (cyanoacrylate) in the container. If the glue has to be used next time, the front end of the syringe stem has to be heated first to have the solidified layer melted before the glue flowing out again. Such methods of having the front end sealed with the polymerization and solidifying, and heating for re-use are usually neglected by user; as a result, the glue in the whole syringe stem will be solidified, and then the whole syringe stem has to be heated for melting the glue. In such a case, before the glue becoming polymerized with a mouth water or natural water, if the container is slightly compressed un-intentionally, a thin film formed with mouth water or natural water will break immediately, and the sealing function of the glue will fail.
Further, the inner surface of the conventional dispensing syringe is a smooth surface, different diameters of dispensing syringes have to be changed to meet actural requirements; otherwise, the dispensing syringe will have a dripping condition, which causes the flowing volume of the glue unable to control.